WMAlbum

WMAlbum is a dock applet that displays album covers for
songs being played by XMMS. You must already have images of
the album covers stored near the file being played. WMAlbum
provides a handy circular menu for play/skip/etc, and can
replace wmxmms. Although dock applets are designed for the
WindowMaker window manager, they also work in other window
managers including openbox and blackbox.
Screenshot while listening to New Order, which I do a lot.
Nifty circular menu.
Nifty circular menu with pause selected.

WMAlbum is underdocumented
but very simple. Place .jpg images of your album covers next
to the mp3 files, and wmalbum will take care of displaying them whenever xmms switches songs. You can control xmms
using the circular menu or use your mouse-wheel to control volume.
Double-click to see the album cover image full-size. Linger, and
a tooltip will appear with the artist and song title.

WMAlbum does not include any album cover images. It does
not include any scripts for automatically fetching them.
It does not use id3 tags, so it does not bloat your mp3's.

WMAlbum requires gdk-pixbuf and xmms to build. gimp-perl is
necessary to rebuild the graphic circular menu, but not necessary
for an ordinary build.
Instructions for debian users are in the readme.